Change Border Color of a JButton in Java Swing preserving the insets

问题

I want to change the border color of a JButton component in Java Swing.

I have tried the following:

package com.example.test;

import java.awt.Color;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test extends JFrame {

    public Test() {

        JPanel panel = new JPanel();
        JButton button1 = new JButton("Test Button 1");
        JButton button2 = new JButton("Test Button 2");
        button2.setBorder(BorderFactory.createLineBorder(Color.RED));

        panel.add(button1);
        panel.add(button2);

        this.add(panel);


        setSize(400, 400);
        setVisible(true);

    }

    public static void main(String[] args) {

        try {
            UIManager.setLookAndFeel( UIManager.getCrossPlatformLookAndFeelClassName() );
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        } catch (UnsupportedLookAndFeelException ex) {
            Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
        }
        Test t = new Test();
    }
}

This generates two buttons, on button2 component I try to change border color but it removes the padding. Is there anyway to preserve the original insets of a standard JButton and just change the color?

Note: I assume that the insets are being removed when assigning the new Border. But I am not 100% sure about it.

回答1:

Instead of creating a LineBorder, use a CompoundBorder:

button2.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(Color.RED, 1), 
            BorderFactory.createEmptyBorder(
                button1.getBorder().getBorderInsets(button1).top, 
                button1.getBorder().getBorderInsets(button1).left, 
                button1.getBorder().getBorderInsets(button1).bottom, 
                button1.getBorder().getBorderInsets(button1).right)));

I took the BorderInsets for the button1 so that both of them have the same size.

My answer is based on @MadProgrammer answer for this question

Btw don't extend JFrame, create an instance of it instead and if you really need to extend a component, be it a JPanel: Extends JFrame vs. creating it inside the program

Also don't forget to call

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

On your JFrame instance, so that your program terminates when you close it.

And also you missed to place your program on the EDT, see more of this on this answer

来源：https://stackoverflow.com/questions/56157666/change-border-color-of-a-jbutton-in-java-swing-preserving-the-insets

标签

java

swing

border

jbutton